Fluid pressure operated jack



Jan. 24, 1939. s. M. PARKER 2,144,892

FLUID PRESSURE OPERATED JACK Filed Nov. 10, 1937 5 Sheets- Sheet lSydney MPar/der 3 Sheets-Sheet 2 S. M. PARKER FLUID PRESSURE OPERATEDJACK Filed Nov. 10, 1937 .Fig. 2.

Jan. 24, 1939.

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Jan. 24, 1939. M PAKER 2,144,892

FLUID PRESSURE OPERATED JACK Filed Nov. 10, 1937 3 Sheets-Sheet 3 Q9 49Fig 4 C 4% LA 14 3 I n ma 1 Ala v63 62- t t 620" +3a R; W F 0 r b Y ,7

E z I E 25a 5 64 S M 64a 25 i a 5 (a) A o 20 o o 20 o O- 20 0 I6 I I 17rm] i ;2 J H r20 \v' [w h .]L'-'. H 2 w 65 a; 40 L 2(8):] a 67 :22 L 6703 66a m 70a m m 69 69a lNVE/VTOQ S dwqq M Par/ ef Patented Jan. 24, 1939farm Parker, mm, assigner tit-Automotive Products Company Illnaea;London. mm

0, 1931, semi No .'1'i3,928 November 117, 1938 g Application November 1I i (carer-40M The invention relates to'fluid pressure actuated j jacks,adapted to be used!or' operatingretractable undercarriages, bomb releasegear oi aircraft and the like." and-provided 'withlockingmechanism'acting tore'tain theiackin either or both of its extremepositions.

-In certain cases when a relatively rigid'structure is usedJmore one'jack "is employed to operate the unit or other oper- *ated element; andin such cases it is desirable that all the lacks should worktogetherfl'and in particular that no one or thelacks should'comme'nee tooperate, ite. extend or contract as the case may be, until all the lacksare unlocked. 16 A risk of distorting" or Jamming theundercarriage' inthe event oi'one or thc"locking means being 'stifler than the other or"others, is thus One object of the present invention is to provide' asystem whichwill' prevent anyoneoia series of Jack's from operatinglmtil all of] the series-are I Another object of the invention is toprovide a fluid actuated having a plurality o! 25 jacks each oi which isproviidedwith individual locking means adapted to'be released bythepressure fluid ted to ia'ck. 'anllfincluding -a valve'deviee whichpreventsfany one ot-said jacks from being-operated until thelocking-m'eans of 30 all the lacks are releasedi s' 1 :Another object ofthe a fluid-actuated system havin'g a piurality oi lacks to be extendedand'contracted in unison, each having individual lockingmeans releasedby5 the pressurejfluldiedto the iachaud including qa valve device oneaehoi the lactate arrest the fluid to the Jack whenthe locking means hasbeen released-and- -to lead said-fluid jtnfanother or the jacks o 7 A]further oblcc'toihthe invention" isprovide a fluid actuated systemincluding arpairoi Jacks :to be operatedin unison; and eachzfltted withindividuallocking means released bv-ithejpressure fluid and includingaval-ve device interposed bev4s tween each-Jack and-the sourcepipressure fluid.-

- said; vaiveudevice being-actuated *bv the locking means of thecorresponding Jack ior leading. the fluid-to the workingspace oi theother iackwhenthe oi, the saidgcorreso spnnwJWk-has beenreleased. i

- Yet a'nother obiectoithe invention isto provide a-iiuidv comprising apair of m o b o a e -huma e o -1* c m source. of fluidprsssurereachfltted with looking 55 rsleasedby' the,saidjpressuraandincluding a changeovervalve device actuated by therespective locking means to prevent either lack from being operateduntil both'locking means are released, 'e'achof said changeover-valvedevices having-a main pipe connection iedwith pressure '5 fluid from thesource and, being adapted to lead "fluid from this main c'onnectiomjto'the corre- "spondinglock-releasing means when the locking means is inaction; or to the working space 0! the other Jack of the pair when thesaid locking 10 meanslsreleased.

Other objects and teaturesof the invention and other novel combinationsof parts and, desirablefi, particular constructions willbe'apparenti'r'om; the following description and from the accom- "l 5panying drawings, in which I A Figure'l is a diagram indicating'ageneral ar'-' rangement used for inter-connecting a pair of jacks havingexternal fluid actuated locking devices;

Figure 2 is a sectional fragmentary elevation through the end o! a Jackto show a construcg' tional form where, the valve device is actuated byan'internaliock; v I v g d Figure 3 is a iragmentary sectional elevationcorresponding to Figure 2 but with the valve v S device in thepositioncorresponding to the unlocked state otthe jack; and

Figure 4 is a diagram illustratlnga modification enabling more thantwojjacks to be'i nterlocked. I. d v

in the example shown in Figure 1 a pair of jack-units lll and H, suchfor example as are ;commonly employed for operating a retractableaircraft undercarriage, are arranged side by side, 'andhave plungermembers I! and i3 respectively adapted to be forced down 'by fluidpressure introduced through pipeconnections II and ii in order toextendthe jaclr and tomove upwardly by passing fluid under pessure'through'the con 40 'nections it and II when the jaci; is required to becontractedor shortened. I

In order that the jacks may be positively held in their fully closedcondition each of'the plungers i2 and n is iormed with a flanges itwhich is adapted tobe engaged bythe'turned in extremities- I910! a pairof locking levers, these being pivoted upon lugs 2| asindicated at 22;At its upper endeach oi the levers is formed with .a siot 23, and theseare'connected-bv a sliding pin 2| witha rod 25 secured to a piston 26diswithin ahydraulic eylinderfl. I A spring v II normally urges thepiston" inan upward :direction and .consequentlyvcauses the lovers 20 tolock the plunger |2 mechanically when it is disposed in its uppermostposition.

The cylinder 21 is extended to form the casing of a valve device 23having a flxed seating 33, which is engaged by the head 3| of a mushroomvalve element when the piston 26 is moved to its lowermost positionduring the process of releasing the locking levers 20, the-stem 32 ofsaid valve element being adapted to engage the piston 26. The valveelement 3|, 32 is, hollow and is arranged to accommodate slidably thestem 33 of a second mushroom valve element having a head portion 34adapted to engage a fixed seating 33 by the action of a coiledcompression spring 36 tending to force apart the two heads 3| and 34. Afurther coiled compression spring 3! acts between the head 3| and theend of the casing 23 so as to keep the stem 32 in flrm contact with thepiston 23. The movement of the stem 33 within the valve element 3|, 32is limited by a pin 38 which is secured to the head 3| and passesthrough a slot 33 in the stem 33. As the piston 23 is moved downwardlyby pressure fluid, as will be hereinafter explained, the spring 31causes the valve element 3|, 32 to follow, while the spring 33 firmlyholds the head 34 of'the second valve element in contact with theseating35. Just before the head 3| reaches the flxed seating 30, however, thepin, 33 contacts with the lower end of the slot 33, and thus the flnalmovement of the valve element .3|, 32 closes the seating 33 and at thesame time causes the head 34 to leave the seating 33. A valve device. ofidentical construction is fltted to the Jack H and is indicatedgenerally at 23a.

The system as a whole is a double-acting one and is supplied with fluidunder pressure to a pipe connection 46 in order to unlock and lower thetwo plungers i2 and I3 while pressure fluid fed into the opposite pipeconnection 4| correspondingly raises the plungers ,|2 and 3 until theyautomatically become locked, a sloping surface 42 on each plunger beingarranged to slide past oblique surfaces 43 on the locking levers 23until such time as the latter are free to move inwardly and hold theplunger in a locked condition. The action of the valve devices 23, 23ain accordance with the invention is as follows. When pressure fluid isfed into the connection 43 it passes into spaces 44 and 44a in therespective valve devices by way of main connections 43 and 45a. Bothjacks being locked, the valve elements are in the positions shown inFigure 1, and therefore the fluid passes through the valve seatings 30,30a and presses downwardly the two pistons 26 and 23a, thus movingoutwardly the lower ends I! of the locking levers 20. At the moment whenthe plungers l2 and I3 are free the heads 3| and 3|a reach the fixedseatings 33 and 30a 50 that the supply of fluid from the main connection45 is transferred past the seating 33 to a pipe 46 which leads to theJack connection l3, thus enabling said fluid to extend the Jack, H.Similarly .the fluid fed through the main connection 43a passes througha pipe connection 43a and has the eil'ect of extending the Jack iii. Inthe event of say the Jack it becoming unlocked rior to the Jack H itwill be seen that the fluid from the main connection 43 is transferredbythe opening of the valve seat 33 to a pipe4la which enables the pressurefluid from the valve device 23 to act upon the piston 23a until suchtime as this piston has 6 mpleted its movement. At the same time press efluid is fed-to the connection l3, but, of course, it cannot effect thea,144,aon

extension of the Jack I until the corresponding locking means have beenreleased. Thus, the two valve devices 23, 23a act as change-over valves,and each feeds either the corresponding locking means or else the otherjack according to the position occupied by the valve elements.

A constructional embodiment of the invention as incorporated in ajackunit of the type dis- "closed in the United States Patent to FrancisVictor Brown No. 2,074,772, issued on March 23rd, 1937, is shown inFigures 2 and 3. The valve devices 23, 230. which are identical inconstruction to those shown in Figure 1, are in this case incorporatedin the respective cylinder heads indicated'at 33 and 30a, and the stem32 of the lower valve element is engaged and is controlled by a cam orspade member 3| associated with the locking means of the jack. Theoperation of these locking means will be clear from the aforementionedUnited States Patent No. 2,074,772, but said means comprises briefly apair of radially slidable detents, one of which is shown at 32, andwhich are notched to engage projections 33 formed upon a pair ofextensions or ears 34 carried by the plunger element of the jack. The

spade member 3| which is connected with the extensions 34 and theplunger by a lost motion device (not shown) is moved downwardly whenpressure fluid is introduced into the space 33 within the jack, and assaid spade member is formed with sloping cam surfaces on its frontand-rear edges when viewed as in Figure 2, this downward movement causesthe detent plungers 32 to be pressed outwardly, thus releasing theplunger of the jack. It will be seen that this downward movement of thespade member 3| also causes the change-over valve device 23 to beactuated, and

. case of the jack l3 this fluid initially passes by way-of the valveseat 33 into the space-33, thus releasing the locking means and movingthe spade member 3| downwardly. When the locking means are completelyreleased the valve seat 33 becomes closed (as seen in Figure 3), and thepressurevfluid from the main connection "therefore passes by way of theconnection 43 to the connection |4a of the other Jack II. It will berealized that if the locking means of this Jack have not-been fullyreleased the pressure "fluid passing through the connection |4a into thespace 330 will assist the unlocking operation.- In the meantime thesupply of pressure fluid to the Jack i3 is cut off, but when the releaseof the locking means inthe Jack H is completed the pressure fluid fromthe main connection 43a then passes through the pipe 43:: and enters thecylinder of the Jack i3 by way of the connection l4.

The method of controlling the input of fluid pressure to the Jacks so asto make sure that all of said jacks are unlocked'before any is allowedto extend (or contract as the casemay'beYmay also be applied'toinstances where a common source of fluid pressure is used to actuatemore than two Jacks, and "a system embodying four of these Jacksrequiring simultaneous operation is illustrated diagrammatically inFigure 4. As

ansaeaa shown, the jacks are associated in pairs and are indicated atin, II and'lla, lie, the input of pressure fluid from a pipe connectionI to the unlocking means of the Jacks I! and II being con- 5 trolled byan auxiliary valve device. indicated at device 60a is associated I valvedevices 29, 29a shown in Figure 1. For actuating the auxiliary valvedevices" and "a however, transverse links N, a are carried by the stems25 and 250 respectively and are connected at their middle points withpush rods 65, "a. The lower end of each of these rods passes slidablythrough the casing of the corresponding auxiliary valve 00 or Gla and isarranged to operate a corresponding valve element it or a. At its upperend this has a mushroom head 81 or "n which when depressed mates with aseating I or "a, while the lower end of the stem 80 or "a has a smallerhead 0! or "a. The stems 66 and "a are pressed upwardly by coiledcompres- .sion springs 10 and "a so as to occupy the positions shownwhen the locking means of the jacks are all operative. Thus whenpressure fluid is fed through the connection OI it is allowed to pass tothe connection 4. and It of the jacks l0 andl I, while the fact that thehead 61a; of the valve '00 is of! its seating 0 enables the pressurefluid similarly to reach the pipe connection llia feeding the valvedevices 620 and a of the jacks illa and lid respectively. The action ineach pair of Jacks is thus exactly the same as that previously describedin connection with the arrangement. shown in Figure 1, the release 01both locking means of any one pair of Jacks causing the centre part ofthe corresponding link 04 or a to be moved downwardly sufficient toclose the valve seating 08 or "a and upon the corresponding passage pastthe head of the value member II or "a in the auxiliary valves. Assumingthat the two jacks II and it become unlocked before the jacks IM and Ilathis will mean that the supply of fluid through the pipe connection inis cut oi!v and the feed through the pipe ll therefore passes through aconnection I! leading to the connection a, which latter it will be seenis already connected with the supply Si by way of the valve seatinglia.Thus, the whole of the fluid pressure is concentrated upon unlocking thelacks Illa. and lid, and when'this has been eflected the consequentlowering of the centre part of the link 0 causes the valve seating "a tobe closed and the passage past the valve head "a to be opened. Thisaction enables fluid from the pipe connection ii to pass thevalve member"a and thus reach the pipe connection ll, from which latter it flowsinto the valve devices O2 and .63 and thence to the cylinder connectionsI4 and I5, since the unlocking of the plungers l2 and it has alreadyopened the valveseating I5 in the manner previously explained. The lacksillustrated are double-acting ones, and the fluid pressure used forclosing or shortening them is supplied through a connection 4| havingbranches connected to the respective cylinders at II, II, "a and 110.

Various modifications may, 0! course, be made in the arrangementsdescribed, and the principle shownin Figure 4 may be extended to embracefeeding the valve devices 62 v any number source of pressure fluid. Incases where the jack is locked in its completely extended position thesame general arrangements can be used, except, of course, that the pipeconnections I4 and I5 to the jack cylinders would be interchanged withthe connections l6 and I1 respectively, suitable modification being madein the mechanical details of the locking mechanism. In some cases it maybe desirable for the plungers to be locked at each extreme position, andfor this purpose the interlocking valve systems shown can be duplicated.

Although this invention has been described in connection with certainspeciflc embodiments, the principles involved are susceptible ofnumerous other applications that will readily occur to persons skilledin the art. The invention is, therefore, to be limited only as indicatedby the scope oi the appended claims. 7

Having thus described the various features of the invention, what Iclaim asnew and desire to secureby Letters Patent is,--

1. A fluid operated system including a plurality of fluid operatedjacks, a locking means for each Jack, means for releasing the lockingmeans by pressure fluid, said releasing means including a feed lineindividual to each jack and its locking means and a valve device in eachof said individual feed lines preventing any oi" said Jacks from beingoperated until the locking means of all the jacks are released.

2. A fluid operated system including a plurality of fluid operatedJacks, a locking means for each jack, means for releasing the lockingmeans by pressure, fluid fed to the jack, and a valve device associatedwith each of said jacks for arresting the flow of fluid to the lack whenthe locking means thereof has been released and leading said fluid toanother of the jacks.

3. A'fluid operated system including a source or fluid pressure, aplurality of fluid operated jacks, a locking means for each lack, avalve device interposed between each jack and the source of pressurefluid, means for releasing the locking means actuated by pressure fluidfed to the valve, andmeans for stopping the flow of fluid to the lockreleasing means of one jack and directing said fluid to the lockreleasing means of another jack.

4. A fluid operated system including a source of fluid pressure, aplurality of jacks each having a worklng'chamber, a locking means foreach jack, means for releasing the locking means by pressure fluid fedto the working chamber of the jack, and a valve device associated witheach of said jacks for arresting the flow of fluid to the Jack when thelocking thereof has been released and leading said fluid to the lockreleasing means and the working chamber of another jack.

6. A fluid operated system including a source of pressure fluid, aplurality of Jacks each having a working chamber, a. locking means foreach jack, means for releasing the locking means by pressure fluid fedto the jack, a change-over valve device interposed between each Jack andthe source of pressure fluid, means for directing the flow of fluid tothe lock releasing means and to the working chamber of one Jack in oneposition of the valve device, and means for stopping the flow of fluidto said jack in another position of the valve device and directing saidfluid to the lock releasing means and the working chamber o'f'anotherJack.

6. A fluid operated system including a source of jacks operated from acommon of pressure fluid, a plurality of fluid operated jacks, a lockingmeans'for each jack, means for releasing the locking means by pressurefluid fed to 'the'jack, a valve device interposed between each jack andthe source of presure fluid, a valve member in said valve devicecontrolling the flow of fluid to the lock releasing means of one jackand which is disengaged from its seat when said lock releasing means isin operative position, an-

other valve member interconnected with the first valve member by a lostmotion connection and which controls the flow of fluid to the lockreleasing means of another jack, said second valve member being engagedwith its seat when the lock releasing means of the 'flrst jack is inoperative position.

7. A fluid operated system according to claim 6 including a mushroomvalve member controlling the flow oi fluid to the lock releasing meansof one Jack, a bore in said valve member, a mushroom valve membercontrolling the flow 0t fluid to the lock releasing means of anotherJack, a stem extending from the other.

8. A fluid operated system including a plurality of fluid operatedjacks, a locking means m each jack, fluid operated means for releasingthe locking means oi one Jaclgfluid operated means for releasing thelocking means of a two-stage valve means for controlling the operationof said lock releasing means, the second stage oi valve operation beingin responseto the release -01 the locking means serving to direct thefluid flow away from said flrst named releasing means, and toward thesecond named releasing means. I

9. A fluid operated system including a source of fluid pressure, aplurality of fluid operated jacks each including a working chamber, alocking means for each Jack, means for releasing the locking means bypressure fluid ted to the Jack, a two-position valve, means connectingthe source of pressure fluid to the lock releasing means and the workingchamber of the jacks'in one position of the valve, and means fordisconnecting the lock releasing means and the working chamber'of oneJack 'and directing the pressure fluid to the other Jack in the otherposition of the valve.

10. A fluid operated system including a plurality o1 fluid operatedlacks, a lockingmeans Ysociated with one set of Jacks, nection betweenthe locking means of said set of Jackie and the said valve deviceadapted to stop the flow oi' pressure fluid to.the,lock releasing 15means or said set 01 Jacks and lead said pressure second valve memberand located in the said bore, and yielding means for spreading saidvalve members one from ananother Jack, and

leasing means of jacks, each set having a working chamber for meansforreleasing the locking means by pres- 10 an operative eonfluid to thelock releasing means and to the working chambers of the other set ofJacks, a

valve device associated with said other set or lacks anoperativeconnection between the lockchambers of the flrstset of jacks.

12.'A fluid operated system rality ,of Jacks and a, locking jack,: meansfor thereof been released, and for leading said fluid to another oithejacks, and means for independently holding one of said valve devicesin io r independently holding one oi said valve devices in position toarrest flow to the associated Jack and jack releasing means, saidresilient 50 means being operative upon release of the locking means forsaid jack.

, SIDNEY ream and leading the pressure fluid to 5 1 another releasingmeans. 1 1. A fluidoperated system including. two sets

